Class (philosophy)
   HOME

TheInfoList



OR:

A class is a collection whose members either fall under a predicate or are classified by a rule. Hence, while a set can be extensionally defined only by its elements, a class has also an intensional dimension that unite its members. When the term 'class' is applied such that it includes those sets elements of which are intended to be collected without a common predicate or rule, the distinction can be indicated by calling such sets "improper class." Philosophers sometimes distinguish classes from
types Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allo ...
and
kinds Kind or KIND may refer to: Concepts * Kindness, the human behaviour * Kind, a basic unit of categorization * Kind (type theory), a concept in logic and computer science * Natural kind, in philosophy * Created kind, often abbreviated to kinds, ...
. We can talk about the ''class'' of human beings, just as we can talk about the ''type'' (or ''natural kind''), human being, or humanity. How, then, might classes differ from types? One might well think they are not actually different categories of being, but typically, while both are treated as abstract objects, classes are not usually treated as
universals In metaphysics, a universal is what particular things have in common, namely characteristics or qualities. In other words, universals are repeatable or recurrent entities that can be instantiated or exemplified by many particular things. For exa ...
, whereas types usually are. Whether natural kinds ought to be considered universals is vexed; see
natural kind "Natural kind" is an intellectual grouping, or categorizing of things, in a manner that is reflective of the actual world and not just human interests. Some treat it as a classification identifying some structure of truth and reality that exists wh ...
. There is, in any case, a difference in how we talk about types or kinds. We say that
Socrates Socrates (; ; –399 BC) was a Greek philosopher from Athens who is credited as the founder of Western philosophy and among the first moral philosophers of the ethical tradition of thought. An enigmatic figure, Socrates authored no te ...
is a '' token'' of a type, or an '' instance'' of the natural kind, ''human'' ''being''. But notice that we say instead that Socrates is a ''member'' of the class of human beings. We would not say that Socrates is a "member" of the type or kind, human beings. Nor would we say he is a type (or kind) of a class. He is a token (instance) of the type (kind). So the linguistic difference is: types (or kinds) have tokens (or instances); classes, on the other hand, have members. The concept of a class is similar to the concept of a set defined by its members. Here, the class is extensional. If, however, a set is defined intensionally, then it is a set of things that meet some requirement to be a member. Thus, such a set can be seen as creating a type. Note that it also creates a class from the extension of the intensional set. A type always has a corresponding class (though that class might have no members), but a class does not necessarily have a corresponding type.


References


External links


"Class" as analytical term in philosophy
Philosophypages.com

* ttp://plato.stanford.edu/entries/logical-atomism/ "Class" as an aspect of logic, and particularly Bertrand Russell"s Principia Mathematica]
"From Aristotle to EA: a type theory for EA" quoted 26/10/2014.
Concepts in logic {{logic-stub